The invention relates to a multiple-thread screw thread arrangement for angular positioning, in the circumferential direction, of a first component having a multiple-thread screw thread pattern relative to a second component having a complementary multiple-thread screw thread pattern, and more particularly, of a threaded closure cap relative to a container member.
For various reasons, it is frequently desirable, especially in the packaging industry, to make a container for storing e.g. cosmetic products, rotationally If asymmetric by making e.g. one portion of a peripheral wall of the container flat, while a remaining peripheral portion may be circular or oval or designed in some other way. If a corresponding, rotationally asymmetric closure cap is to be placed on such a container, as is frequently desired so as to provide a complete combination of container and cap with an aesthetically pleasing appearance, it has to be ensured that the closure cap is always aligned in a specific manner relative to the container when in the closed position; otherwise, parts thereof might project out relative to the container and thus would not only detract from the external appearance of the combination but could also cause difficulties when transporting and storing it. Moreover, an advertising slogan extending across the two parts of the combination might be interrupted thereby. In the case of closure caps that are attached to the container by axial snap-on, the desired alignment can be obtained comparatively easily by providing the two parts with features that only permit snap-on when the cap has a particular angular alignment relative to the container. Naturally however, such a solution to the problem is not suitable for threaded closure caps. In contrast to snap-on, the fixing of a closure cap to a container by screwing it on has the advantage that this allows a more user-friendly and less forceful operation.
It is an object of the invention to provide, in a rotationally asymmetric combination of a first component and a second component in which the first component can be screwed onto the second component, a combination in which the first component always comes to rest at a particular angular alignment relative to the second component when it is in a fully screwed position relative to the first component. It is a further object of the invention to provide, in a rotationally asymmetric combination of a first component and a second component in which the first component can be screwed onto the second component, a combination in which a predetermined angular alignment of the first component relative to the second component in a fully screwed position thereof can be obtained without requiring special care in handling the first component while it is being screwed on.
In accordance with one aspect of the invention, these and other objects are achieved by a screw thread arrangement for the angular positioning, in the circumferential direction, of a first component having a multiple-thread screw thread pattern relative to a second component having a complementary multiple-thread screw thread pattern, in particular of a threaded closure cap relative to a container member, in which thread runouts (thread runouts being outer-end portions of thread turns which first engage thread turns of the complementary component) of the multiple-thread screw thread patterns of each component are angularly spaced from each other in the circumferential direction, wherein, a first angular spacing between positions of adjacent turn runouts when viewed in a circumferential direction differs from a second angular spacing between positions of adjacent thread runouts.
In accordance with an alternative aspect of the invention a screw thread arrangement for the angular positioning, in the circumferential direction, of a first component having a multiple-thread screw thread pattern relative to a second component having a complementary multiple-thread screw thread pattern, in particular of a threaded closure cap relative to a container member, is provided in which the thread runouts of the multiple-thread screw thread patterns of each component are angularly spaced from each other in the circumferential direction, wherein a dimension of at least one thread turn of each multiple-thread screw thread pattern is different from that of other thread turns
When a threaded closure cap provided with a screw thread arrangement according to the invention is to be screwed onto a container member, a particular angular mutual alignment of the two parts is initially required so as to bring the co-operating turns of the threads on the cap and the container member into mutual alignment and thereby allow them to be screwed onto one another. In other words: the cap cannot be screwed on at any arbitrary angular alignment thereof relative to the container member. This does not require careful handling on the part of the user however, since the alignment is automatically set or made perceptible by an initial, tentative rotation of the closure cap. Consequently, by appropriate dimensioning of the screw path, it can be achieved that the closure cap always adopts a particular position relative to the container member when it is in its fully screwed-on state. The external appearance of a combination of a closure cap and a container having congruent rotationally asymmetric shapes is thereby free of projections and allows advertising slogans to be placed on e.g. flat overlapping peripheral portions of the two parts.
The invention both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing